Apparatus for forming threads and filaments of fluorocarbon resin and method thereof

ABSTRACT

An apparatus for forming and producing elongated threads or filaments of synthetic material such as fluorocarbon resins which can be used to form yarns utilizes, a turning machine having, a chuck assembly for mounting a billet of the fluorocarbon resin material therein, and a lead screw assembly with a tool holder assembly thereon. The lead screw assembly is disposed to move a cutting tool in the tool holder assembly longitudinally and parallel to the axes of rotation of the billet so that a plurality of cutting edges on the end cutting face of the cutting tool can cut simultaneously from the billet a corresponding plurality of sized, shaped and dimensioned threads or filaments which can be combined and formed into the desired yarn. Means are provided to synchronize the movement of the cutting tool with the rotation of the fluorocarbon resin billet. 
     Additionally, the apparatus and method as above described wherein a plurality of spaced cutting tools are disposed for simultaneous engagement of the billet each adapted to cut threads or filaments therefrom.

BACKGROUND OF THE INVENTION

This invention relates generally to an apparatus for forming andproducing filaments or elongated strands of synthetic material such asfluorocarbon resins that can be used to form yarns which can be woven,knitted, braided or otherwise combined to provide a plurality ofproducts adapted to improve service and life for many conventionalapplications.

It is well known that fluorocarbon resin fibers and filament such aspolytetrafluoroethylene (PTFE); fluoroethylene propylene (FEP) and otherpolymers and co-polymers are adapted and have been used to form wovenand knitted materials because of the chemical and physical properties ofsuch fluorocarbon resins in that they are chemically inert, heat andcorrosion resistant, easy to clean, and have a built in lubricity.

For a more detailed discussion of the properties and applications offluorocarbon resin fibers and filaments reference is herein made to thepublication entitled Du Pont Technical Information - Fibers - BulletinT-13 dated March 1970 which is incorporated herein by reference.

In this Bulletin, it is shown that PTFE fibers and filaments in woven,knitted and braded forms are widely used in many industrial applicationsand in products where the desirable chemical and physicalcharacteristics of these materials act to improve the function thereof.

For example the woven, knitted and braided materials made fromfluorocarbon resin filaments or elongated strands are used for all typesof clothing, for filter bags and filtering cloths, at industrial andcommercial sites where there are chemical processes, chemicals or wastematerial of a highly corrosive nature and/or corrosive hot gases or hotliquids; and for applications such as woven self-lubricated bearings;for braided packing, for lacing cord and other electronic industryapplications; and for many medical uses.

Various methods for producing PTFE fibers, filaments and elongatedstrands for making articles are known in the prior art. For many yearsthe making of such articles followed the practices of the textileindustries in that the yarns have been made from fibers which areobtained from dispersions of fluorocarbon resins. More recentlymechanical techniques have been developed utilizing foil slittingwherein a thin layer of PTFE is skived from a billet of the samematerial and the layer is then slit into threads or filament by means ofsuitable slitting jigs. For example one technique of this type is shownin U.S. Pat. No. 2,728,950.

In U.S. Pat. No. 4,025,598 another mechanical method for formingthreads, elongated strands, or filaments of PTFE is shown in which thesurface of a billet of PTFE being rotated is deformed by a jig to form aplurality of grooves and ridges and then a skiving knife is applied tocut the ridges off to form the desired filament. The filament can be aslong as desired and can be drawn off heated and stretched and combinedwith other filaments to form a conventional multi-filament yarn whichcan then be utilized to form the woven, knitted or braided material.

The present invention is directed to an improved apparatus for themechanical forming of PTFE filaments or elongated strands wherein arotating billet of PTFE is engaged by a cutting tool having a pluralityof sized offset cutting edges so that a plurality of separate sized andshaped filaments of PTFE can be simultaneously cut in continuous lengthsso that the filaments can be drawn off, joined and stretched inaccordance with conventional techniques to form yarns of variousthickness.

The broad method of making filaments or elongated strands offluorocarbon resin in accordance with the present invention permits avariety of techniques and variations to provide a desired shape and sizefor the filaments as is more fully described hereinafter. Furtherhowever it will be understood by those skilled in the art that whilethis apparatus and method is shown as applied to a billet offluorocarbon resin material that it is equally appli-cable to otherductile materials such as steel, copper or aluminum. Waste is minimizedcompared with other methods for producing plastic filaments or "METALWOOLS".

Further the present apparatus and method can be applied to a simplecompression molded billet of fluorocarbon resin which is a cheaper rawmaterial then the raw materials now used in the prior art for making thefluorocarbon fibers to provide the desired yarn for forming the woven,knitted or braided materials of fluorocarbon resin.

The strands or filaments obtained by the method and apparatus of thepresent invention can be used as cut from the fluorocarbon resin billetor they can be moderately or highly oriented to alter their physicalcharacteristics by calendering or stretching at room or elevatedtemperatures. Further, because of the versatility of the presentapparatus and method the actual dimensions of the filaments or elongatedstrands can be varied over a wide range by adjusting the pitch and depthof cut of the cutting device for establishing the desired cross-sectionfor the respective filament or elongated strands of fluorocarbon resin.

SUMMARY OF THE INVENTION

Thus the present invention covers an apparatus for forming elongatedthreads or filaments of synthetic material such as fluorocarbon resinfrom a billet thereof comprising, a turning machine having, a chuckassembly mounted for rotation therein about a fixed axis, driving meansfor rotating the chuck assembly, at least one sized billet of syntheticmaterial fixedly mounted in said chuck for rotation therewith when thedriving means is placed in operation, a tool holder assembly operativelyconnected on the turning machine for longitudinal movement at apredetermined rate parallel to the axis of rotation of the chuckassembly and the billet connected therein, and means to adjust said toolholder assembly towards and away from the axis of rotation of saidbillet, a cutting tool fixedly mounted in and movable with the toolholder assembly to engage and cut into said rotating billet, and saidcutting tool having a shaped cutting face with at least two offsetcutting edges thereon whereby a plurality of sized and shaped threadsand filaments are cut from the billet simultaneously.

Additionally the apparatus as above described wherein the longitudinalmotion of the tool holder assembly parallel to the fixed axis ofrotation for the chuck assembly is synchronized by means of a gear trainwith the rotation of the chuck and billet to produce a thread orfilament of constant cross-section.

Additionally the apparatus as above described in combination with amicro-processor for controlling the rate of longitudinal motion of thetool holder assembly parallel to the fixed axis of rotation for thechuck assembly to produce a thread or filament of varying cross-section.

Accordingly it is an object of the present invention to provide animproved apparatus for making elongated threads and filaments ofsynthetic material of uniform shape and size.

It is another object of the present invention to provide an improvedapparatus for making elongated threads and filaments which is relativelysimple and reliable and which can produce threads and filaments ofvarying shapes and sizes.

It is another object of the present invention to provide an improvedapparatus for mechanically forming a plurality of elongated threads andfilaments simultaneously from a billet of synthetic material such asfluorocarbon resin.

It is another object of the present invention to provide an improvedapparatus for mechanically forming a plurality of elongated threads orfilaments simultaneously from a billet of synthetic material such asfluorocarbon resin wherein the shape, size and dimension of each of saidplurality of elongated threads or filaments can be easily controlled andvaried as may be required.

With these and other objects and advantages the invention will be betterunderstood by reference to the description which follows with referenceto the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagramatic perspective view of a turning machine with alead screw, showing a billet of synthetic material such as fluorocarbonresin held in the chuck assembly thereon, and showing one form of toolholder assembly and a cutting tool in operative association therewith inthe initial cutting position to begin forming the elongated threads andfilaments, all in accordance with the present invention.

FIG. 2 is an enlarged end view of the billet and cutting tool in theinitial position as shown in FIG. 1.

FIG. 3 is an enlarged perspective view of a fragment of the billet andcutting tool shown in FIG. 1 wherein all of the cutting edges of thetool are in engagement with the rotating billet and the plurality ofelongated threads or filaments are being simultaneously formed.

FIG. 4 is a top view of the cutting tool in cutting engagement with thebillet as shown in FIG. 3 showing in phantomized lines the cutting tooladvancing into the billet during the cutting of the elongated threadsand filaments as shown in FIG. 3.

FIG. 4A is an enlarged cross-section of an elongated thread or filamentas formed and cut by one of the cutting sections of the cutting toolshown in FIG. 4.

FIG. 5 is an end view of the offset cutting faces shown in FIGS. 1 to 4of the drawings.

FIG. 6 is a left side view of the cutting tool shown in FIGS. 1 to 4 ofthe drawings.

FIG. 7 is a vertical section taken on line 7--7 of FIG. 5.

FIG. 8 is an enlarged perspective view of the offset cutting face of thecutting tool shown in FIGS. 1 to 6 of the drawings.

FIG. 9 is an enlarged top view of the cutting end of the tool shown inFIGS. 1 to 8 having dimensions illustrated thereon for forming anelongated thread or filament which is generally rectangular incross-section and wherein the length and width dimensions for thecross-section are 0.005"×0.015".

FIG. 10 shows another form of cutting tool having shaped cutting edgesfor forming elongated threads or filaments which have a cross-section inrhomboid form.

FIG. 10A is an enlarged cross-section of the rhomboid form of elongatedthread or filament formed and cut by the cutting tool shown in FIG. 10.

FIG. 11 shows another form of cutting tool with shaped cutting edges toprovide elongated threads and filaments having at least two parallelcurved faces.

FIG. 11 A is an enlarged cross-section of the elongated thread orfilament formed and cut by the cutting tool shown in FIG. 11.

FIG. 12 shows another form of cutting tool with shaped cutting edges toprovide elongated threads and filaments which vary in at least onedimension from the next adjacent thread or filament cut by these cuttingedges.

FIGS. 12A, 12B, and 12C are respectively enlarged cross-sections of thevariations of the elongated threads or filaments cut with the respectivecutting edges of the tool shown in FIG. 12.

FIG. 13 is a top view of still another form of cutting tool having afurther modified set of cutting edges or sections to permit increasingthe surface speed of the billet of ductile material when cuttingelongated threads or filaments therefrom having relatively largecross-sectional areas.

FIG. 14 is an end view of the offset cutting face of the cutting toolshown in FIG. 13.

FIG. 15 is a left side view of the cutting tool shown in FIG. 13.

FIG. 16 is an enlarged perspective view of the offset cutting face ofthe cutting tool shown in FIGS. 13 to 15 of the drawings.

FIG. 17 is a schematic fragmentary perspective view showing a billet ofsynthetic material such as fluorocarbon resin held in the chuck assemblythereon and showing at least two spaced cutting tools disposed in theinitial cutting position to begin forming the elongated threads andfilaments all in accordance with this modified form of the presentinvention.

FIG. 18 is a view of a fragment of the billet and the spaced cuttingtools shown in FIG. 8 wherein all the cutting edges of each of therespective cutting tools are in engagement with the rotating billet sothat the plurality of elongated threads or filaments can besimultaneously formed by each of the respective cutting tools.

The present invention contemplates a method of forming elongated threadsand filaments from a billet of ductile synthetic material such asflurocarbon resin in accordance with the following steps:

a. Mounting said billet of synthetic material for rotation about a fixedaxis,

b. moving a cutting tool longitudinally and parallel to the axis ofrotation of said billet and into engagement with the peripheral face ofthe billet as it is being rotated,

c. said cutting tool having a plurality of shaped and sized cuttingedges thereon to simultaneously cut a plurality of shaped, sized anddimensioned elongated threads or filaments from the billet when the toolis moved into engagement therewith, and

d. synchronizing the longitudinal movement of the cutting tool with therotation of the billet to produce a fiber of constant cross-section.

The method of the present invention also contemplate varying the cuttingedges of the cutting tool to vary the shape, size and dimension of eachof the plurality of elongated threads or filaments which aresimultaneously cut from the billet of synthetic material, and varyingthe number of cutting tools with the above mentioned different cuttingedges.

Alternatively the method of the present invention contemplates adjustingthe longitudinal movement of the cutting tool by a micro-processor toprovide threads or filaments of varying cross-sectional widths.

DESCRIPTION OF THE INVENTION

Referring to the drawings FIG. 1 shows diagrammatically a turningmachine such as a screw cutting engine lathe generally designated 1having a chuck assembly 2 mounted thereon for holding and rotating abillet 3 of ductile synthetic material such as fluorocarbon resin.

A screw cutting engine lathe with a chuck assembly as diagrammaticallyillustrated in FIG. 1 is driven by any suitable type of driving assembly4 which includes a suitable gear train arrangement for rotating thebillet 4 at a rate of rotation that will permit threads or filaments offluorocarbin resin to be cut from the billet as is more fully describedhereinafter. Turning machines such as screw cutting engine lathes ofthis type are well known and easily purchaseable on the open market,therefore the turning machine 1 will not be described in great detailherein.

Thus, in one form of screw cutting engine lathe for use in connectionwith the present invention, a lead screw attachment generally designated5 is provided as shown in FIG. 1. Lead screw attachment 5 includes, atool holder support 6 mounted for longitudinal movement along the bed 7of the screw cutting engine lathe 1. The tool holder support 6 isoperatively associated with an elongated threaded shaft or lead screw 6amounted on the lathe 1 parallel to the longitudinal axis of the head ofthe lathe and the fixed axis of rotation for the chuck assembly 2.Fixedly connected and movable with the tool holder support 6, is a toolholder assembly 8 which includes, a tool support 9 having a slot 10therethrough in which a cutting tool 11 can be mounted and locked inassembled position by any suitable threaded means such as the bolt 12.Thus when the tool holder support 6 and the tool holder assembly 8 aremoved by the threaded shaft or lead screw 6a, the cutting tool 11hereinafter more fully described will be moved longitudinally andparallel to the axis of rotation for the chuck 2 and billet 3 thereinand can be so adjusted that it will commence initial cutting engagementwith the peripheral surface of the billet 3 adjacent to the free end asis shown in FIGS. 1, 3 and 4 of the drawings.

The threaded shaft 6a is rotatably mounted in spaced bearings, notshown, in the turning lathe 1 and is driven by a suitable driving meansgenerally designated 13 which is connected to the threaded shaft 6a byany suitable type of reduction gears generally designated 14 so that therate of rotation of the threaded shaft 6a can be synchronized with therate of rotation of the chuck assembly 2 and billet 3 of flurocarbonresin material.

Lead screw attachments for moving tool holder assemblies and the drivingmeans for such lead screw attachment are well known in the art, easilypurchaseable on the open market and therefore are not more fullydescribed herein.

Alternatively, the operation of the threaded shaft 6a, driving means 13and reduction gears 14 may be controlled by any suitable type ofmicro-processor generally designated 15 so that the rate of rotation ofthe threaded shaft 6a and therefore the longitudinal movement of thetool holder assembly 8 can either be constant or can be varied duringoperation.

The cutting tool 11 is particularly designed and assembled on the toolholder 9 so that it can be moved into position to cut from the billet 3simultaneously a plurality of elongated threads or filaments 20a, 20b,20c, 20d, and 20e, as is shown in FIGS. 3 and 4 of the drawings.

In order to achieve this advantageous result the cutting tool 11 asshown in FIGS. 1 to 9 of the drawings is an elongated member generallysquare or rectangular in cross-section. The cutting tool 11 is providedat one end with an offset cutting face generally designated 21 to form aplurality of offset or stepped cutting edges as at 22a, 22b, 22c, 22dand 22e shown in FIGS. 3 to 9 of the drawings.

Each of the cutting edges 22a to 22e are spaced from the next adjacentcutting edge a predetermined distance as represented by the offsets asat 23a, 23b, 23c and 23d.

The length of the cutting edges 22a to 22e, are shown as A in FIG. 4.This distance A determines one dimension A of the filament cross-sectionas shown at FIG. 4A, and is fixed for a given cutting tool. If adifferent dimension A is required, a new tool must be produced.

The length of the offsets, 23a to 23e, are shown as B in FIG. 4. Thisdistance B, determines the maximum value for dimension B of the filamentcross-section as shown in FIG. 4A. The actual value of dimension B for agiven filament in turn is determined by the setting of the longitudinalfeed rate, that is, the advance of the tool per revolution of thebillet. A filament therefor may have a dimension B anywhere between zeroand the length of offset 23a to 23e depending on the setting of thelongitudinal feed rate.

FIG. 9 is a top view of a typical cutting tool with dimensions as shown.The dimension A for the filament as shown in FIG. 4A produced by thistool is determined by the length of the cutting edges, 22a to 22e, inthis case 0.005". The length of the offsets, 23a to 23e is 0.015".Therefore as shown by FIG. 4A the dimension B of the filament producedby this tool can be anywhere between almost zero and b 0.015" dependingupon the setting of the longitudinal feed rate.

Thus, for a given cutting tool by varying the length of the cuttingedges 22b to 22e, and the offsets, 23a to 23d, and by controlling thelongitudinal feed rate, elongated fibers or filaments withcross-sectional dimensions in a range from 0.002"×0.002" to0.100"×0.100" can be easily achieved.

Further the number of cutting edges and offsets on the cutting tool isdetermined by the desired denier of the fiber bundle or yarn which isformed from the individual elongated threads or filaments after they arecut. Denier is the weight in grams of 9000 meters of a given yarn soformed.

Thus with a given cutting tool, for example the cutting tool 11 as shownin FIGS. 1 to 9 of the drawings, various denier of a given yarn can beproduced by either changing the longitudinal feed rate or by separatingthe filaments as they are being spooled.

The offset cutting face 21 of the cutting tool 11 can be varied toproduce different quadralateral cross-sectional shapes for the elongatedthreads or filaments 20a to 20e cut from the billet 3.

Thus by reference to FIG. 10, a cutting tool 50 is shown having acutting face generally designated 51 which has sloped cutting edges asat 52a, 52b, 52c and 52d and offsets as at 53a, 53b, and 53c. Thiscutting tool will produce an elongated thread or filament having arhomboid shaped cross-section as is shown in enlarged form at FIG. 10A.

In FIG. 11 the cutting tool 60 has an offset cutting face generallydesignated 61 which has curved cutting edges as at 62a, 62b and 62c andoffsets as at 63a, 63b, 63c and 63d. This cutting tool will produce anelongated thread or filament having a cross-sectional form in which twosides will be parallel and two sides will have a curved shape as isshown in the enlarged section at FIG. 11A of the drawings.

In FIG. 12 the cutting tool 70 has an offset cutting face generallydesignated 71 with unequal length cutting edges as at 72a, 72b, 72c and72d and spaced offsets of equal length as at 73a, 73b and 73c. This toolwould produce elongated filaments in which one dimension A as shown inFIGS. 12A, 12B, and 12c, will vary from filament to filament and theother dimension B as shown in FIGS. 12A, 12B and 12C will be constantand be determined by the longitudinal feed setting.

OPERATION

In operation the screw cutting engine lathe 1 is first assembled so thatthe billet 3 is mounted in the chuck assembly 2 and aligned to establisha fixed axis of rotation for the billet 3.

The tool 11 is positioned in the opening 10 so that the longitudinalline thereof will intersect the center line of the axis of rotation forthe billet 3 when the lead screw assembly 5 causes the tool holderassembly 8 to move the tool 11 into engagement with the end face 3a ofthe billet 3.

The motor 13 is placed into operation so that the motor 13 and geartrain 14 will drive the threaded member 6 to cause the tool holderassembly 8 to move the cutting tool 11 into engagement with the billet3.

As the cutting edges 22a to 22e and 23a to 23d enter into engagementwith the end of the billet 3 the cutting tool will commence cutting thethreads or filaments 20a20b, 20c, 20d and 20e from the face of thebillet 3 each thread or filament being removed simultaneously intact andserially from the billet 3.

As long as the billet 3 rotates and the movement of the cutting edgesare synchronized with such rotation, the individual threads or filaments20a to 20e will be removed continuously and will have an indefinitelength sufficient to enable the threads to be taken off singly or woundtogether to form a multi-filament yarn of predetermined denier as afunction of the dimensions A and B which are established by the cuttingtool and the longitudinal movement thereof.

Those skilled in the art will readily understand that the yarn thusformed can be subjected to additional treatment such as calendering orstretching at ambient temperature, at below ambient temperature or atelevated temperatures to orient the fibers, and thus increase thetensile strength of the yarn formed from the elongated threads orfilaments 20a to 20e, which techniques are well known in the art.

Because cutting conditions by the method and apparatus above describedare not ideal, the physical properties such as the tensile strength areaffected by the surface speed of the billet. Thus if a certain criticalsurface speed for a given cross-sectional area of the elongated threador filament being formed is exceeded, the elongated thread or filamentbeing produced will contain minute fractures which reduces the tensilestrength and the degree of elongation for the particular elongatedthread or filament.

In the operation of the method and apparatus as above described, it hasbeen determined that the smaller the cross-sectional area of theelongated thread or filament being formed, the higher the allowablesurface speed for the billet of ductile material. Thus when makingelongated threads or filaments having relatively small cross-sectionalareas in the area of 0.002"×0.002" surface speeds as high as 500' perminute can be used. Conversely when making larger filaments in the orderof 0.10"×0.010", the billet must be run at a lesser surface speed ofabout 200' per minute.

It is however possible to achieve higher surface speeds beforefracturing occurs during the manufacture of elongated threads orfilaments which have relatively larger cross-sectional areas bymodifying the cutting edge of the cutting tool as is shown in FIGS. 13to 16 of the drawing. Thus in FIG. 13 and 14, the cutting tool 80 isshown as having an offset cutting face 81 wherein the cutting edges areat 82a, 82b, 82c, 82d and 82e and the offsets are at 83a, 83b, 83c and83d. Additionally, the top face of the cutting tool 80 will be angled asat 84a, 84b, 84c, 84d and 84e.

FIG. 16, the perspective view clearly shows how the top surface of thecutting tool 11 adjacent the cutting edges is modified or cut back bythe grooves 84a, 84b, 84c, 84d and 84e at an angle to provide a positivetop rake. This acts to reduce the forces exerted during cutting of thebillet 3 and allows a higher cutting speed to be used before surfacefracturing of the filament occurs.

ANOTHER EMBODIMENT OF THE INVENTION

In FIGS. 17 and 18 another embodiment of the invention is shown in whichspaced tool holders are provided as at 9' and 9" in which cutting tools11' and 11" respectively are mounted in the same manner above describedfor the cutting tool 11.

The cutting tools 11' and 11" may be identical with any of the cuttingtools shown in FIGS. 4, 10, 11, 12, and 13 described above. Similarlythe transverse cutting faces and the longitudinal movement of thecutting tool 11' and 11" will also be identical with the transversecutting faces above described for the cutting tools 11, 50, 60, 70 and80 described above.

In this arrangement the multiplicity of cutting tools can be used toproduce more then one bundle of yarn with each longitudinal pass of thespaced cutting tool across the billet 3.

Thus a relatively simple mechanical means for forming a plurality ofelongated threads or filaments has been described. These threads andfilaments can be formed into yarns of predetermined denier which can beeffectively utilized for the formation of products for which thecharacteristics of synthetic material such as fluorocarbon resins arereadily adaptable.

It will be understood that the invention is not to be limited to thespecific construction or arrangement of parts shown but that they may bewidely modified within the invention defined by the claims.

What is claimed is:
 1. Apparatus for forming elongated threads orfilaments of synthetic material such as fluorocarbon resin from a billetthereof comprising:a. a chuck assembly mounted for rotation in saidapparatus about a fixed axis, b. driving means for rotating the chuckassembly about said fixed axis, c. at least one sized billet of ductilematerial fixedly mounted on said chuck assembly for rotation therewithwhen the driving means is placed in operation, d. a tool holder assemblyoperatively connected on the apparatus for longitudinal movement, e.means for moving the tool holder assembly at a predetermined rateparallel to the axis of rotation of the chuck assembly and the billetconnected thereto, f. a cutting tool fixedly mounted on and movable withthe tool holder assembly parallel to the axis of rotation of the chuckassembly and movable with respect to the tool holder toward and awayfrom the axis of rotation of said billet to engage and cut into saidbillet when the same is rotated with the chuck assembly, and g. saidcutting tool having shaped transverse cutting face means, with at leasttwo shaped cutting edges and at least two offsets which space saidcutting edges, for simulataneously cutting at least two sized and shapedthreads and filaments in elongated form from the billet corresponding tothe at least two shaped cutting edges.
 2. In the apparatus as claimed inclaim 1 wherein:a. the shaped cutting edges on the end cutting face ofthe cutting tool are parallel to the longitudinal line of the cuttingtool and have a predetermined length to form one of the dimensions forthreads and filaments generally square and rectangular in cross-section,and b. said offsets on the end cutting face are transverse to thelongitudinal line of the cutting tool and have a predetermined lengthfor forming the other dimension for threads or filaments generallysquare and rectangular in cross-section as a function of thepredetermined rate of longitudinal movement of the tool holder assembly.3. In the apparatus as claimed in claim 1 wherein;a. the shaped cuttingedges on the end cutting face of the cutting tool are sloped at an angleto the longitudinal line of the cutting tool and have a predeterminedlength to form one of the dimensions for threads and filaments generallyrhomboid in cross-section, and b. said offsets on the end cutting faceare transverse to the longitudinal line of the cutting tool and have apredetermined length to form the other dimensions for threads orfilaments generally rhomboid in cross-section as a function of thepredetermined rate of longitudinal movement of the tool holder assembly.4. In the apparatus as claimed in claim 1 wherein;a. the shaped edges onthe end cutting face of the cutting tool are curved and have apredetermined length to form one of the dimensions for threads orfilaments having at least one curved side in cross-section, and b. saidoffsets on the end cutting face are transverse to the longitudinal lineof the cutting tool and have a predetermined length for forming theother dimensions for threads or filaments generally having one curvedside in cross-section as a function of the predetermined rate oflongitudinal movement of the tool holder assembly.
 5. In the apparatusas claimed in claim 1 wherein;a. the shaped cutting edges on the endcutting face of the cutting tool are parallel to the longitudinal lineof the cutting tool and each have a different predetermined length thanthe next adjacent shaped cutting edge to form different lengths of oneof the dimensions for threads or filaments generally rectangular incross-section, and b. said offsets on the end cutting face aretransverse to the longitudinal line of the cutting tool and have apredetermined length to form the other dimension for the respectivethreads or filaments generally rectangular in cross-section as afunction of the predetermined rate of longitudinal movement of the toolholder assembly.
 6. In the apparatus as claimed in any of claims 2, 3, 4or 5 wherein;a. said cutting edges have a predetermined length to cutone of said dimensions of the cross-sectional shape of the threads andfilaments in a range from 0.001" to 0.100", and b. said offsets have alength so that the predetermined longitudinal movement will cut thesecond dimension in a range from 0.001" to 0.100".
 7. In the apparatusas claimed in claim 1 wherein the ductile material is a synthetic resinfrom the group of fluorocarbon resins, namely polytetrafluoroethylene,fluoroethylene propylene and like polymers and co-polymers thereof. 8.In the apparatus as claimed in claim 1 including, a micro-processor forcontrolling the longitudinal movement of the tool holder assembly andfor synchronizing the same with the rotation of the chuck assembly andbillet to produce a predetermined cross-sectional size for the elongatedthread and filament cut from the billet by the cutting tool.
 9. In theapparatus as claimed in claim 1 wherein;a. the tool holder assemblyoperatively connected in the turning machine has at least two spacedcutting tool holders thereon, and b. a cutting tool respectively mountedin each of said cutting tool holders, and c. each of said tool holdershaving an end cutting face sized and shaped to cut the elongated threadsand filaments to a given shape in cross-section, each end cutting faceincluding at least two shaped cutting edges and at least two offsetswhich space the respective cutting edges, each end cutting facesimultaneously cutting at least two sized and shaped threads andfilaments in elongated form from the billet.
 10. In the apparatus asclaimed in claim 9 wherein;a. at least one of said cutting tools has anend cutting face shaped to cut filaments generally square incross-sectiion.
 11. In the apparatus as claimed in claim 9 wherein, atleast one of said cutting tools has, a transverse cutting face shaped tocut the elongated threads and filaments generally rhomboid incross-section.
 12. In the apparatus as claimed in claim 9 wherein atleast one of said cutting tools have an end cutting face shaped to cutelongated threads and filaments having one side curved in cross-section.13. In the apparatus as claimed in claim 9 wherein at least one of saidcutting tools have, an end cutting face with cutting edges thereinhaving different lengths whereby the adjacent elongated threads andfilaments cut by said at least one cutting tool will have one of thedimensions different from the dimension of the next adjacent elongatedthread or filament.
 14. In the apparatus as claimed in claim 9including, a micro-processor for controlling the longitudinal movementof the tool holder assembly and for synchronizing the same with therotation of the chuck assembly and billet to produce a predeterminedcross-sectional size for the elongated threads and filaments cut fromthe billet by the cutting tools on the spaced cutting tool holders. 15.A method of forming elongated threads and filaments from a billet ofductile synthetic material such as fluorocarbon resin comprising thesteps of:a. mounting said billet of synthetic material for rotationabout a fixed axis, and b. simultaneously cutting a plurality of shapedand sized elongated threads and filaments from the billet including thesteps of:(i) adjusting a cutting tool having a shaped transverse cuttingface with a plurality of shaped and sized cutting edges and a pluralityof offsets which space said cutting edges, in the radial direction withrespect to said fixed axis, and (ii) moving said cutting tool in alongitudinal direction parallel to said fixed axis at a predeterminedrate into contact with said billet such that said plurality of cuttingedges simultaneously cut said plurality of shaped and sized elongatedthreads and filaments from the billet.
 16. The method of formingelongated threads and filaments as claimed in claim 15 including thestep of, varying the longitudinal movement of the cutting tool toprovide threads and filaments of varying cross-sections.
 17. The methodof forming elongated threads and filaments as claimed in claim 15including the steps of;a. shaping and sizing the cutting edges of thecutting tool to provide elongated threads and filaments generally squarein cross-section.
 18. The method of forming elongated threads andfilaments as claimed in claim 15 including the steps of;a. shaping andsizing the cutting edges of the cutting tool to provide elongatedthreads and filaments generally square in cross-section, b. thecross-sections so formed having a length dimension in a range from0.001" to 0.100", and c. so synchronizing and controlling thelongitudinal movement of the cutting tool to provide a width dimensionin a range from 0.001" to 0.100".
 19. The method of forming elongatedfibers and filaments as claimed in claim 15 including the steps of,shaping and sizing the cutting edges of the cutting tools to provideelongated threads and filaments generally rhomboid in cross-section. 20.The method of forming elongated fibers and filaments as claimed in claim15 including the steps of, shaping and sizing the cutting edges of thecutting tools to provide elongated threads and filaments having aquadralateral cross-section with at least one curved side.
 21. In theapparatus as claimed in claim 1, wherein said at least two cutting edgesare offset from each other in a direction substantially perpendicular tosaid axis of rotation to form stepped cutting edges.